<p>Having two <code>cases</code> in a <code>switch</code> statement or two branches in an <code>if</code> chain with the same implementation is at
best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then in an <code>if</code> chain they should
be combined, or for a <code>switch</code>, one should fall through to the other. </p>
<h2>Noncompliant Code Example</h2>
<pre>
switch (i) {
  case 1:
    doFirstThing();
    doSomething();
    break;
  case 2:
    doSomethingDifferent();
    break;
  case 3:  // Noncompliant; duplicates case 1's implementation
    doFirstThing();
    doSomething();
    break;
  default:
    doTheRest();
}

if (a &gt;= 0 &amp;&amp; a &lt; 10) {
  doFirstThing();
  doTheThing();
}
else if (a &gt;= 10 &amp;&amp; a &lt; 20) {
  doTheOtherThing();
}
else if (a &gt;= 20 &amp;&amp; a &lt; 50) {
  doFirstThing();
  doTheThing();  // Noncompliant; duplicates first condition
}
else {
  doTheRest();
}
</pre>
<h2>Exceptions</h2>
<p>Blocks in an <code>if</code> chain that contain a single line of code are ignored, as are blocks in a <code>switch</code> statement that contain a
single line of code with or without a following <code>break</code>.</p>
<pre>
if (a == 1) {
  doSomething();  //no issue, usually this is done on purpose to increase the readability
} else if (a == 2) {
  doSomethingElse();
} else {
  doSomething();
}
</pre>
<p>But this exception does not apply to <code>if</code> chains without <code>else</code>-s, or to <code>switch</code>-es without default clauses when
all branches have the same single line of code. In case of <code>if</code> chains with <code>else</code>-s, or of <code>switch</code>-es with default
clauses, rule {rule:java:S3923} raises a bug. </p>
<pre>
if (a == 1) {
  doSomething();  //Noncompliant, this might have been done on purpose but probably not
} else if (a == 2) {
  doSomething();
}
</pre>

